Surgical scalpel with retractable blade guard

ABSTRACT

A scalpel is provided with a blade guard which is mounted for movement between a blade-guarded position and a blade-exposed position and an actuating mechanism for the blade guard is positioned in such a way that the fingers of the surgeon automatically engage the mechanism when the scalpel is held in its normal position of use. The actuating mechanism is coupled to the blade guard through a linkage assembly which causes the blade guard to move over a substantially greater distance than the distance which the surgeon&#39;s fingers move in operating the actuating mechanism. In a preferred embodiment, the blade guard slides over a linear path, the actuating mechanism comprises a tongue-like structure integral with the scalpel, and the linkage assembly comprises a plurality of pivotally interconnected lever arms. One of the lever arms is positioned so as to be captured in a detent mechanism when the blade guard is fully retracted to its blade-exposed position.

FIELD OF THE INVENTION

The present invention relates generally to surgical knives and, moreparticularly, concerns a surgical scalpel which, in use, automaticallymoves a protective guard in and out of a protective position over theblade of the knife.

BACKGROUND OF THE INVENTION

Surgical scalpels are a class of knives which are manufactured inaccordance with particular stringent standards, in order to assure theirquality and precision of handling. It goes without saying that the bladeof the knife must be sharp and of the finest quality, but the entireinstrument must be of such a weight and size as to fit well and becomfortable within the hand of the surgeon. In addition, it must bewell-balanced, to be capable of precise manipulation, and it must besmall enough so as not to obstruct the surgeon's view of the blade whilein use.

In the sometimes harried atmosphere of an operating room, a surgeon mustoften work quickly, handing instruments back and forth to assistants.With sharp implements, such as scalpels, the danger of accidentalcutting or jabbing of operating room personnel is ever present.Furthermore, certain fatal infections, such as the AIDS virus can betransferred to individuals through minor cuts, when even smallquantities of blood are mixed. In a sense, a minor operating room injurycan ultimately prove to be fatal.

Scalpels have been provided with removable guards to prevent contactwith the blade when not in use. For example, U.S. Pat. No. 4,735,202issued to R. W. Williams on Apr. 5, 1988 discloses a scalpel in whichthe blade guard is provided in the form of a sleeve which is slidablymounted over the scalpel and may be locked into position over the bladewhen not in use. Although such a blade guard could be used effectivelyprior to starting and after completing a surgical procedure, it couldnormally not be used and would be of no value during the procedureitself. A primary reason is that two hands are required to position theblade guard, and the surgeon typically has only one hand available forthe scalpel during the procedure. Furthermore, even if the surgeon wereable to use both hands, the scalpel would be unacceptable, because thesurgeon's attention is distracted from the procedure whenever he musthandled the scalpel. In addition, the surgeon risks injuring himselfwith the scalpel every time he must bring his second hand into use.Thus, the scalpel disclosed in this patent would be used in the openposition during an entire surgical procedure and, for all intents andpurposes, the blade guard is unavailable during the procedure. Varioustypes of utilities knives have been provided with blade guards thatslide from a blade-guarded position to a blade-exposed position bymanually operating a lever which is coupled to the blade guard so thatthe pivoting movement of the lever is converted to the sliding movementof the blade guard. Such knives are disclosed in U.S. Pat. No. 4,757,612issued July 19, 1988 to Peyrot and U.S. Pat. No. 2,380,787 issued July31, 1945 to Pierce et al. These knives have the advantage that the guardoperating lever is operated by the same hand which holds the knife and,therefore, the blade guard may be moved in and out of position in asingle-handed operation.

However, such utilities knives are gripped in the hand of the operatorin a manner similar to a tennis racket. Surgical scalpels, on the otherhand, are held between the fingers delicately, in a manner similar to apencil. Thus, while the utility knives may be operated in the manner ofa bicycle hand brake, the scalpel can only be pressed between the thumband the forefinger, and the range of manual movement available tooperate it is substantially less, on the order of one-quarter toone-half inch. On the other hand, it is essential that the blade guardbe moved clear of the scalpel blade when the scalpel is being used, inorder that the surgeon's view of the blade be entirely unobstructed.Typically, this requires that the blade guard move over a distance atleast as great as an inch. In addition, it is essential that the bladeguard be operated without changing position of the hand. That is, theblade guard must be operated while maintaining the hand in the positionin which a scalpel is normally held. Otherwise, it could interfere withthe surgical procedure. In addition, the pressure required to operatethe blade guard should be no greater than the finger pressure requiredto hold the scalpel, in order to avoid fatigue and cramping of thesurgeon's hand.

Broadly, it is an object of the present invention to provide a scalpelwith a protective blade guard which can be operated by the hand holdingthe scalpel so as to move the guard between a blade-guarded and ablade-exposed position. It is specifically intended that the blade guardbe so moved when the scalpel is grasped in its position of normal use.

It is another object of the present invention to provide a scalpel withan automatically retractable blade guard which fits well and comfortablywithin the hand of the surgeon, is capable of precise manipulation, anddoes not obstruct the surgeon's view of the blade while in use.

It is another object of the present invention to provide a scalpel witha retractable blade guard in which the finger pressure required toretract the guard is comparable to the finger pressure required to holdthe scalpel while in use.

It is another object of the present invention to provide a scalpel witha retractable blade guard in which the distance moved by the fingers ofthe surgeon while moving the blade guard between blade-exposed andblade-guarded positions is substantially less than the distance moved bythe blade guard between these positions.

It is also an object of the present invention to provide a scalpel witha retractable blade guard which is simple and convenient in use andrelatively inexpensive in construction.

In accordance with the present invention, a scalpel is provided with ablade guard which is mounted for movement between a blade-guardedposition and a blade-exposed position and an actuating mechanism for theblade guard is positioned in such a way that the fingers of the surgeonautomatically engage the mechanism when the scalpel is held in itsnormal position of use. The actuating mechanism is coupled to the bladeguard through a linkage assembly which causes the blade guard to moveover a substantially greater distance than the distance which thesurgeon's fingers move in operating the actuating mechanism. In apreferred embodiment, the blade guard slides over a linear path, theactuating mechanism comprises a tongue-like structure integral with thescalpel, and the linkage assembly comprises a plurality of pivotallyinterconnected lever arms. One of the lever arms is positioned so as tobe captured in a detent mechanism when the blade guard is fullyretracted to its blade-exposed position.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of thepresent invention will be understood more completely from the followingdetailed description of presently preferred, but nonethelessillustrative, embodiments of the present invention, with reference beinghad to the accompanying drawings, in which:

FIG. 1 is a right side view of a first embodiment of a scalpel inaccordance with the invention, with portions cut away to show structuraldetails, the protective guard being shown in the blade-guarded position;

FIG. 2 is a top view of the scalpel of FIG. 1;

FIG. 3 is sectional view of the scalpel, on an enlarged scale, takenalong line 3--3 in FIG. 1 and looking in the direction of the arrows;

FIG. 4 is a sectional view similar to FIG. 3 taken along line 4--4 inFIG. 1 and looking in the direction of the arrows;

FIG. 5 is a sectional view similar to FIG. 3 taken lines 5--5 in FIG. 1and looking in the direction of the arrows;

FIG. 6 is a top view similar to FIG. 2, showing the scalpel with theprotective guard fully retracted to the blade-exposed position;

FIG. 7 is a right-side view similar to FIG. 1 showing the protectiveguard fully retracted;

FIG. 8 is a fragmentary top view of a second embodiment of a scalpel inaccordance with the present invention, with portions shown in sections,to facilitate description of structural details;

FIG. 9 is fragmentary right-side view of the scalpel in FIG. 8;

FIG. 10 is a fragmentary sectional view, on an enlarged scale, takenalong lines 10--10 in FIG. 8 and looking in direction of the arrows;

FIG. 11 is a fragmentary top view of a third embodiment of a scalpel inaccordance with the present invention;

FIG. 12 is a right-side view of the scalpel of FIG. 11;

FIG. 13 is a fragmentary top view of a fourth embodiment of a scalpel inaccordance with the invention; and

FIG. 14 is a right-side of the scalpel of the FIG. 14, with the acuatingarm mechanism removed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the details of the drawings, FIGS. 1-7 illustrate apreferred embodiment 10 of a scalpel embodying the present invention.Scalpel 10 broadly comprises: a handle or holder 12; a blade 14detachably secured to handle 12; a blade guard 16 acting as a protectivesheathe for blade 14; an actuating arm 18; and a linkage assembly 20connecting the actuating arm 18 with the blade guard 16.

In use, the scalpel is operated by being held in the hand and depressingthe actuating arm 18 towards body 12. Such movement is coupled throughthe linkage assembly 20 to the blade guard 16, causing it to slidebackwards to expose the blade 14 (compare FIGS. 2 and 6). As can be seenin FIG. 6, when the blade 14 is fully exposed, scalpel 10 is held in thehand in the normal position of use.

Handle 12 is preferably made of high quality stainless steel, althoughit could equally well be made of any other material which is used forsurgical knives. Actuating arm 18 is preferably made of the samematerial and is formed integrally with handle 12. By arching actuatingarm 18 outward slightly, it cooperates with handle 12 to form atong-like structure. The inherent resilience of the actuator arm willensure that it returns to the position shown in FIG. 2 upon beingreleased. At its forward end, arm 12 is fashioned with a fitting 22 todetachably receive and retain the blade 14. This fitting is preferablyof a standard type, so that the conventional blades of various shapesand sizes may be interchanged.

At a distance behind the blade fitting 22, handle 12 is provided with alaterally projecting supporting post 24 for the linkage assembly 20.Behind post 24, there is provided a bore 12a which passes entirelythrough ;arm 12. Immediately behind bore 12a, arm 12 is formed with aslight outwardly flared projection 26 which serves as a finger rest, andthe actuating arm 18 is correspondingly flared at 28 to form a similarfinger rest. In addition, the under surface at the forward end of arm 18is formed with an abruptly terminating ramp portion 18a (see FIG. 7), todefine a detenting mechanism, to be discussed in detail below.

Blade guard 16 is also preferably made of stainless steel, and itsfinish preferably matches the finish of handle 12 and actuating arm 18.As can be seen in FIG. 3, the forward end of guard 16 is preferablyformed into a U-shaped channel, so as to cover all sharp portions of theblade. This protective portion of guard 16 is preferably formed with acut out 16a near the rear of the blade guard (See FIG. 7), so as toavoid interference with arm 24 and the mechanical linkage 20. Inaddition,, a slit 16b is provided near the bottom of guard 16 behindcut-out 16a. At its rear, guard 16 is formed into a thin, elongated rail30, which extends rearwardly for a substantial distance. Handle 12 isformed with a shallow groove 12b, which receives rail 30 with a close,free-sliding tolerance and serves as a guideway therefore. Rail 30 isretained within groove 12b by means of a rivet 32, or the like.Alternatively, handle 12 could be formed with any type of elementaffixed below groove 12b which overlaps rail 30 so as to retain it.

The linkage assembly 20 includes a generally L-shape arm 34 and astraight arm 36. The L-shape arm is pivotally mounted to post 24 at 38.A pivotable connection 40 is provided between arms 34 and 36, and asimilar pivotable connection 42 is provided between arm 36 and actuatingarm 18. As can be seen in FIG. 3, the longer leg of L-shape arm 34 isnot formed in a single plane, but, in fact, includes a bend at 34a, soas to form an angle in a plane perpendicular to the L-shape (see FIG.3). Arm 36 extends through aperture 12a in handle 12, and the longer legof arm 34 extends through slit 16b in guard 16. The free end of arm 34is formed into a ball shape 34b, or the like, to prevent it fromaccidentally pulling out of slot 16b.

The scalpel 10 also includes a safety lock 50, which prevents bladeguard 16 from being retracted. The scalpel may then be handled safely,without the danger of accidentally uncovering the blade and causinginjury. Safety lock 50 includes a slide member 52 having a generallyinverted U-shape. The right hand leg 54 of slide member 52 extends intoa channel 12c in handle 12, which channel is an extension of channel12b. The left hand leg 56 of slide member 52 includes a vertical slot56a, which permits the slide member 52 to be secured to handle 12 bymeans of a rivet 58 and a resilient washer 60.

In operation, the vertical slot 56a permits slide member 52 to betranslated vertically with respect to arm 12 from a locked position(shown in FIG. 1 and in solid lines in FIG. 5) to an unlocked position(shown in FIG. 7 and in broken lines in FIG. 5). Rivet 58 and washer 60assure that member 52 will be retained in the selected position as aresult of increased friction. In the locked position, leg 54 isinterposed in groove 12b behind rail 30, so that blade guard 16 cannotslide backwards. When slide member 52 is moved to its unlocked or raisedposition, arm 54 is withdrawn from behind rail 30, so that the plateguard 16 may be retracted. It is contemplated that the safety lock 50would normally be in its locked position, until the surgeon is preparedto use scalpel 10. At that time, the safety lock 50 would be unlocked,to permit the blade guard 16 to be moved freely in and out of theblade-guarded position.

From the above description, it will be appreciated that when the scalpel10 is grasped in the user's hand in the position of normal use,actuating arm 18 will be forced towards handle 12, as shown in FIG. 6.Inasmuch as actuating arm 18 is coupled to the shorter leg of arm 34(the shorter leg is substantially shorter and preferably 1/3 to 1/2 thelength of the longer leg), actuating arm 18 is moved over asubstantially shorter distance than the distance over which blade guard16 slides in exposing the blade (compare FIGS. 2 and 6). As will beappreciated from FIGS. 6 and 7, as the blade guard 16 moves rearward,the longer leg of arm 34 slides downwardly along the inclined surface18a on arm 18 and is ultimately captured behind the abrupt edge 18b,which forms a detent mechanism. The inherent resilience in arm 34 thenholds it in position and prevents the blade guard from sliding forward.When the surgeon has completed using the scalpel, he simply applies aslight downward force to ball end 34b. This frees the longer leg of arm34 from the detent 18b, and the inherent resilience of arm 18 pulls itaway from handle 12, pulling arm 36 with it. As a result, arm 36 causesarm 34 to rotate in a clockwise direction, and blade guard 16 isreturned to its blade-guarded position.

Referring now to FIGS. 8-10, there is disclosed a second embodiment 110of a scalpel in accordance with the present invention. In thisembodiment, and all other embodiments that follow, elements which areessentially the same as the corresponding elements in embodiment 10 areindicated with the same reference characters and will not be describedany further. Scalpel 110 differs from scalpel 10 essentially in thespecifics of the linkage assembly, which is here indicated by thereference character 120. This linkage assembly includes an arcuate rackelement 122 projecting laterally from actuating arm 18 and through anopening in handle 12. A linear rack element 124 is provided on the innersurface of blade guard 16. In addition, there is provided a lower pinion126 which meshes with rack 122 and an upper pinion 128 which meshes withrack 124. Pinions 126 and 128 are mounted on a common axle 130 so as torotate together, and the ratio between the number of teeth on therespective pinions is selected so that rack 124 will move asubstantially greater distance than rack 122. The manner of using thescalpel 110 and its overall operation will be essentially the same asscalpel 10.

FIGS. 11 and 12 illustrate a third embodiment 210 of a scalpel inaccordance with the present invention. Again, the difference in thisembodiment resides in the linkage assembly, now indicated as 220. Thislinkage assembly includes a shuttle member 222 which is slidably mountedon handle 12. Shuttle member 222 is connected to actuating arm 18through an arm 224, which is pivotally mounted to both the actuating arm18 and the angle member 222. An arm 226 is pivotally mounted to post 24at one end, and the other end of the arm extends through a slot 222a inshuttle member 222 and a slot 16b in blade guard 16.

In operation, urging actuating arm 18 towards body 12 causes arm 224 topivot with respect to shuttle member 222, which is forced to sliderearwardly. As shuttle member 222 moves rearwardly, it causes arm 226 topivot in a clockwise direction, drawing blade guard 16 rearwardly. Whenactuating arm 18 is released, its resilience causes the reversemovement, and blade guard 16 is returned to its blade-guarded position.

FIGS. 13 and 14 illustrate a fourth embodiment 310 of a scalpel inaccordance with the present invention. As indicated schematically inphantom image 316', in the present embodiment, the blade guard 116rotates so as to expose the blade 14. In scalpel 310, linkage assembly320 includes a shaft 322 which extends inwardly from actuating arm 18towards handle 12. Shaft 322 is formed by axially twisting a rod with asquare cross section. This produces a spiral distortion of the rod.Blade guard 316 is rotatably mounted to handle 12 and includes a squarehole 316a, which conforms in size to the cross-section of shaft 322.

In operation, as actuating arm 18 is forced towards handle 12, shaft 322is pressed into hole 316a, and blade guard 316 rotates, in order tofollow the spiral distortion of the shaft. By design, blade guard 316 isrotated approximately 180° to the blade-exposed position when actuatingarm 18 is fully depressed. With the blade 14 exposed, the scalpel may beused in the normal manner. When actuating arm 18 is released, theresilience of the arm and a helping spring 324 force shaft 322 away fromhandle 12, causing blade guard 316 to return to its blade-guardedposition. In the present embodiment, the magnified movement of bladeguard 316 as compared to the actuating shaft is achieved through therotation of the blade guard.

Although preferred embodiments of the invention have been disclosed forillustrative purposes, those skilled in the art will appreciate thatvarious modifications, additions and substitutions are possible, withoutdeparting from the scope and spirit of the invention as disclosed in theaccompanying claims.

We claim:
 1. A scalpel comprising:an elongated handle having front andrear ends; a substantially planar surgical blade secured at the frontend of said handle, said blade having a direction of cut extending alongthe length of the handle; actuating means disposed in a position to beengaged by the fingers of a user when holding the scalpel in a positionof normal use and mounted for movement generally perpendicular to theplane of said blade and the direction of cut thereof relative to saidhandle; a blade guard constructed to cover at least any sharp portionsof said blade and mounted for movement between a blade-guarded positionin which said blade is covered and a blade-exposed position in whichsaid blade may be used for cutting; and linkage means for coupling themovement of said actuating means to said blade guard so as to move thesame between said blade-guarded and blade-exposed positions, saidlinkage means including means for causing the amount of movement of saidblade guard to be substantially greater than the amount of movement ofsaid actuating means.
 2. A scalpel in accordance with claim 1 whereinsaid actuating means comprises a resilient actuating arm mounted at therear of said handle so that a forward portion of said actuating arm isat a distance from said handle, whereby said actuating arm and saidhandle cooperate in the manner of a pair of tongs, said linkage meansbeing connected to the forward end of said actuating arm.
 3. A scalpelin accordance with claim 1 wherein said blade guard is mounted forsliding movement along said handle.
 4. A scalpel in accordance withclaim 1 wherein said linkage means comprises first rack means coupled tobe moved by movement of said actuating means, second rack means on saidblade guard, and pinion means for coupling movement of said first rackmeans to said second rack means so that the amount of movement of saidsecond rack means is substantially greater than the amount of movementof said first rack means.
 5. A scalpel in accordance with claim 4wherein said actuating means comprises a resilient actuating arm mountedat the rear of said handle so that a forward portion of said actuatingarm is at a distance from said handle, whereby said actuating arm andsaid handle cooperate in the manner of a pair of tongs, said linkagemeans being connected to the forward end of said actuating arm.
 6. Ascalpel in accordance with claim 5 wherein said blade guard is mountedfor sliding movement along said handle.
 7. A scalpel in accordance withclaim 4 wherein said blade guard is mounted for sliding movement alongsaid handle.
 8. A scalpel in accordance with claim 4 wherein said pinionmeans comprises a first pinion meshed with said first rack means, asecond pinion meshed with said second rack means and means coupling saidfirst and second pinions for rotation together, the ratio of the numberof teeth between said first and second pinions being selected to achievesubstantially greater movement of said second rack means than said firstrack means.
 9. A scalpel in accordance with claim 1 further comprisinglocking means mounted on said handle for adjustment relative to saidhandle so as to prevent movement of said blade guard from saidblade-guarded position to said blade-exposed position, said lockingmeans being also adjustable to permit free movement of said blade guardbetween said blade-guarded and said blade-exposed positions.
 10. Ascalpel comprising:a handle having front and rear ends; a surgical bladesecured at the front end of said handle; actuating means disposed in aposition to be engaged by the fingers of a user when holding the scalpelin a position of normal use and mounted for movement relative to saidhandle; a blade guard constructed to cover at least any sharp portionsof said blade and mounted for movement between a blade-guarded positionin which said blade is covered and a blade-exposed position in whichsaid blade may be used for cutting, said blade guard being mounted forsliding movement along said handle; and linkage means for coupling themovement of said actuating means to said blade guard so as to move thesame between said blade-guarded and blade-exposed positions, saidlinkage means being constructed so that the amount of movement of saidblade guard is substantially greater than the amount of movement of saidactuating means; said linkage means comprising an L-shaped arm havingone leg of said L substantially shorter than the other, the vertex ofsaid L-shaped arm being mounted for pivotal movement with respect tosaid handle at a distance laterally thereof, the shorter leg of saidL-shaped arm being coupled to receive the movement of said actuatingmeans and the longer leg of said arm being connected to said blade guardso as to impart a sliding movement thereto when said L-shaped arm ispivoted.
 11. A scalpel in accordance with claim 10 wherein saidactuating means comprises a resilient actuating arm mounted at the rearof said handle so that a forward portion of said actuating arm is at adistance from said handle, whereby said actuating arm and said handlecooperate in the manner of a pair of tongs, said linkage means beingconnected to the forward end of said actuating arm.
 12. A scalpel inaccordance with claim 10 further comprising detent means for capturing aportion of one of said L-shaped arm and said actuating arm when saidblade is in its blade-exposed position.
 13. A scalpel comprising:ahandle having front and rear ends; a surgical blade secured at the frontend of said handle; actuating means disposed in a position to be engagedby the fingers of a user when holding the scalpel in a position ofnormal use and mounted for movement relative to said handle; a bladeguard constructed to cover at least any sharp portions of said blade andmounted for movement between a blade-guarded position in which saidblade is covered and a blade-exposed position in which said blade may beused for cutting; and linkage means for coupling the movement of saidactuating means to said blade guard so as to move the same between saidblade-guarded and blade-exposed positions, said linkage means beingconstructed so that the amount of movement of said blade guard issubstantially greater than the amount of movement of said actuatingmeans; said linkage means comprising a first arm having a first endmounted for pivotal movement relative to said handle at a distancelaterally thereof and a second end connected to said blade guard so asto couple pivotal movement of said first arm as sliding movement of saidblade guard; shuttle means mounted for sliding movement along saidhandle; means coupling said actuating means to said shuttle means forconverting the movement of said actuating means to sliding movement ofsaid shuttle means; and means coupling said shuttle means to said firstarm for converting the sliding movement of said shuttle means toproportionate rotational movement of said arm.
 14. A scalpel inaccordance with claim 13 wherein said actuating means comprises aresilient actuating arm mounted at the rear of said handle so that aforward portion of said actuating arm is at a distance from said handle,whereby said actuating arm and said handle cooperate in the manner of apair of tongs, said linkage means being connected to the forward end ofsaid actuating arm.
 15. A scalpel in accordance with claim 14 whereinsaid blade guard is mounted for sliding movement along said handle. 16.A scalpel in accordance with claim 13 wherein said blade guard ismounted for sliding movement along said handle.
 17. A scalpel inaccordance with claim 13 wherein said blade guard is mounted forrotational movement relative to said handle, said linkage meanscomprising means for converting the movement of said actuating means toproportionate rotational movement of said blade guard.
 18. A scalpel inaccordance with claim 17 wherein said actuating means comprises aresilient actuating arm mounted at the rear of said handle so that aforward portion of said actuating arm is at a distance from said handle,whereby said actuating arm and said handle cooperate in the manner of apair of tongs, said linkage means being connected to the forward end ofsaid actuating arm.
 19. A scalpel in accordance with claim 17 whereinsaid coupling means comprises a rod having a polygonal cross sectionalshape extending between said actuating arm and said blade guard, saidblade guard having an aperture therein conforming in shape and size tothe cross section of said rod, said rod having been axially twisted soas to impart of permanent spiral distortion thereto.
 20. A method forautomatically guarding and exposing the substantially planar blade of asurgical scalpel having an elongated handle and a direction of cutextending along the length of the handle comprising the stepsof:providing a blade guard over said blade which is mounted so as to bemoved from a blade-guarded position to a blade-exposed position;positioning an actuating member on said scalpel so as to be movedgenerally perpendicular to the plane of the blade and the direction ofcut by the fingers of a user when the scalpel is grasped for normal use;and coupling the actuator member movement to said blade guard so thatthe blade guard is moved over a substantially greater distance than saidactuating member.